Germanwings flight 4U9525: Doing nothing?

We all greeted the news of the crash of Germanwings flight 4U9525 with saddness. We all greeted the news that Germanwings flight 4U9525 had been crashed into a mountain side by co pilot Andreas Lubitz with shock.
Inevitably, there have been calls for greater checks on recruits. The tragic irony was that the security feature – the door that could be sealed from the cockpit – that was supposed to protect the passengers – against the actions of suicidal terrorists – was the feature that caused their deaths at the hands of a deranged employee.
Tragically, we could well find that all that could have been done had been done and there is little further to be done – except allow the friends and relatives of the victims of Andreas Lubitz to greive and to mourn their loss.